This invention relates to compositions useful as lubricant and fuel additives and methods for improving the operation of internal combustion engines, specifically by reducing the amount of fuel consumed by such engines. More particularly, the invention comprises lubricating compositions which may be used in such engines to decrease fuel consumption, and a method of using such lubricating compositions to accomplish this purpose. This invention also relates to a method for preparing these compositions. Additionally, this invention relates to concentrates and fuel composition comprising these compositions.
Efforts to reduce the amount of fuel consumed by internal combustion engines such as automobile engines have increased in recent years as a result of the petroleum shortage, the increased cost of petroleum products, and the desire for conservation of natural resources such as petroleum. It is recognized that a situation under which fuel consumption is minimized is desirable, both because of the conservation factor and because such a situation is economical for the user of the engine.
Many of the proposed solutions to the fuel conservation problem have been mechanical as, for example, adjusting the engine for a leaner burn or simply building smaller cars and smaller engines. Other efforts have related to developing lubricants that reduce the overall friction of the engine thereby reducing energy requirements. Some synthetic lubricants have been developed and compounded for use in the automobile engine to reduce fuel consumption. A considerable amount of effort has been expended toward developing additives for use in mineral lubricating oils and greases to reduce the friction properties of the oils and greases.
The following publications are exemplary of art in this area:
U.S. Pat. No. 3,796,663 describes N-hydroxy hydrocarbyl-substituted cyclic imides of C.sub.4 -C.sub.5 dicarboxylic acids, e.g., hydrocarbyl-substituted succinyl and glutaric hydroximides, as rust inhibition, wear reduction and frictional control additives for lubricating oils.
U.S. Pat. No. 4,104,182 describes a lubricating oil composition comprising a hydrocarbyl oil of lubricating viscosity, a metal-containing additive characterized by promoting the formation of hard deposits in an internal combustion engine, and a hydrocarbon-substituted succinimide represented by the formula: ##STR3## in which R is an aliphatic hydrocarbon radical having from about 1 to 50 carbon atoms and R' is a hydrocarbon radical having from 3 to 20 carbon atoms, and a method for lubricating an internal combustion engine.
U.S. Pat. No. 4,325,827 describes a fuel efficient motor oil which contains a friction-reducing amount of an N-hydroxymethyl C.sub.12-36 aliphatic hydrocarbyl succinimide. This patent also describes these additives as being used in liquid hydrocarobn engine fuel.
European patent application No. 20,037 describes oil soluble C.sub.12-36 aliphatic hydrocarbyl succinimide or succinamide which provides a friction reducing effect where it is incorporated in a lubricating oil.